Moore C W
Department of Microbiology, City University of New York Medical School/Sophie Davis School of Biomedical Education, New York 10031.
Antimicrob Agents Chemother. 1994 Jul;38(7):1615-9. doi: 10.1128/AAC.38.7.1615.
Lesions introduced into cellular DNAs prelabeled with [2-14C]thymidine or [6-3H]thymidine, as well as cell killing, were inhibited by the presence of EDTA during 20-min reactions of Saccharomyces cerevisiae cells with the low-molecular-weight bleomycin family of anticancer antibiotics. In contrast, the level of killing by low concentrations of bleomycin was higher among cells which had grown for three generations in defined synthetic complete medium supplemented with ferrous sulfate than among cells grown without iron supplementation. In S. cerevisiae, the uptake of iron is facilitated by a plasma membrane ferric reductase activity and a high-affinity (Km = 5 x 10(-6) M) ferrous uptake system. Lethal effects of 1.3 x 10(-6) M bleomycin increased approximately 50% with 10(-5) M Fe(II), nearly twofold with 10(-4) M Fe(II), and 2.8 times with 10(-3) M Fe(II). Thus, iron preloading is a new experimental approach to increasing and studying the effects of the glycopeptides on cellular DNAs and other cellular targets. This approach could also be used for studying and better understanding DNA repair genes and could serve as a model for studies of redox active chemicals in biological systems.
在用[2-¹⁴C]胸苷或[6-³H]胸苷预标记的细胞DNA中引入的损伤，以及细胞杀伤，在酿酒酵母细胞与低分子量博来霉素类抗癌抗生素进行20分钟反应期间，因EDTA的存在而受到抑制。相比之下，在添加硫酸亚铁的限定合成完全培养基中生长了三代的细胞中，低浓度博来霉素的杀伤水平高于未添加铁的培养基中生长的细胞。在酿酒酵母中，质膜铁还原酶活性和高亲和力（Km = 5×10⁻⁶M）亚铁摄取系统促进铁的摄取。1.3×10⁻⁶M博来霉素的致死效应在添加10⁻⁵M Fe(II)时增加约50%，在添加10⁻⁴M Fe(II)时增加近两倍，在添加10⁻³M Fe(II)时增加2.8倍。因此，铁预加载是一种增加和研究糖肽对细胞DNA和其他细胞靶点作用的新实验方法。这种方法也可用于研究和更好地理解DNA修复基因，并可作为生物系统中氧化还原活性化学物质研究的模型。
